Methods of making a mixture of salts of gamma-hydroxybutyrate

ABSTRACT

Provided herein are pharmaceutical compositions and formulations comprising mixed salts of gamma-hydroxybutyrate (GHB). Also provided herein are methods of making the pharmaceutical compositions and formulations, and methods of their use for the treatment of sleep disorders such as apnea, sleep time disturbances, narcolepsy, cataplexy, sleep paralysis, hypnagogic hallucination, sleep arousal, insomnia, and nocturnal myoclonus.

1. CROSS REFERENCE

This application is a continuation of U.S. patent application Ser. No.14/045,673, filed Oct. 3, 2013, which is a continuation of U.S. patentapplication Ser. No. 13/739,886, filed Jan. 11, 2013, which claims thebenefit of U.S. Provisional Patent Application No. 61/737,695, filedDec. 14, 2012, the content of each of which is hereby incorporated byreference in its entirety into this application.

2. FIELD OF THE INVENTION

Provided herein are pharmaceutical compositions and formulationscomprising salts of gamma-hydroxybutyrate (GHB). In a preferredembodiment, the salts encompass more than one type of cation. Alsoprovided herein are methods of making the pharmaceutical compositionsand formulations, and methods of their use for the treatment ofdisorders including fibromyalgia and sleep disorders. Such sleepdisorders include apnea, sleep time disturbances, narcolepsy, cataplexy,sleep paralysis, hypnagogic hallucination, sleep arousal, insomnia, andnocturnal myoclonus.

3. BACKGROUND OF THE INVENTION

Gamma-hydroxybutyrate (GHB), also known as “oxybate,” is an endrogenouscompound with hypnotic properties that is found in many human bodytissues. GHB is present, for example, in the mammalian brain and othertissues. In the brain, the highest GHB concentration is found in thehypothalamus and basal ganglia and GHB is postulated to function as aneurotransmitter (See Snead and Morley, 1981, Brain Res. 227(4):579-89). The neurophamtacologic effects of GHB include increases inbrain acetylcholine, increases in brain dopamine, inhibition of GABA-ketoglutarate transaminase and depression of glucose utilization butnot oxygen consumption in the brain. GHB treatment substantially reducesthe signs and symptoms of narcolepsy, i.e., daytime sleepiness,cataplexy, sleep paralysis, and hypnagogic hallucinations. In addition,GHB increases total sleep time and REM sleep, and it decreases REMlatency, reduces sleep apnea, and improves general anesthesia (see,e.g., U.S. Pat. Nos. 6,472,431; 6,780,889; 7,262,219; 7,851,506;8,263,650; and 8,324,275; each of which is incorporated herein byreference in its entirety).

Sodium oxybate (Na.GHB), commerically sold as Xyrem®, is approved forthe treatment of excessive daytime sleepiness and cataplexy in patientswith narcolepsy. Na.GHB has also been reported to be effective forrelieving pain and improving function in patients with fibromyalgiasyndrome (See Scharf et al., 2003, J. Rheumatol. 30: 1070; Russell etal., 2009, Arthritis. Rheum. 60: 299), and in alleviating excessivedaytime sleepiness and fatigue in patients with Parkinson's disease,improving myoclonus and essential tremor, and reducing tardivedyskinesia and bipolar disorder (See Ondo et al., 2008, Arch. Neural.65: 1337; Frucht et al., 2005, Neurology 65: 1967; Berner, 2008, J.Clin. Psychiatry 69: 862).

Xyrem®, for use with patients with narcolepsy, is a chronically usedproduct which requires high levels of the drug. The amount of sodiumintake from the drug significantly increases the dietary sodium intakefor patients, which is undesirable for patients with hypertension, heartdisease, renal disease or at risk of stroke. Further, despite a generalrecord of safety when used as prescribed, there are risks of abuse andmisuse of Xyrem® which can cause serious medical problems, includingseizures, loss of consciousness, coma, and death (see, e.g., FDA productlabel dated Nov. 13, 2006 for NDA no. 021196).

Little research has been done on salts of GHB, other than Na.GHB, and weare not aware of any combining multiple salts (see, e.g., U.S. Pat. Nos.4,393,236; 4,983,632; 6,472,431; Ferris and Went, 2012, Forensic ScienceInternational 216: 158-162).

Thus, there is a need for GHB formulations that minimize the undesirableside effects of the sodium, particularly in patients with hypertension,heart disease, renal disease or at risk of stroke, yet provideadditional health benefits from the presence of the other salts. It isdesireable that such modified formulations provide good solubility,stability and purity in order to provide safe, effective and consistentdoses to patients, and also display acceptable phalinacodynamic andphalinacokinetic properties.

4. SUMMARY OF THE INVENTION

Provided herein are pharmaceutical compositions comprising salts ofgamma-hydroxybutyrate (GHB) which are useful in the treatment ofconditions responsive to GHB, for example, fibromyalgia and sleepdisorders such as apnea, sleep time disturbances, narcolepsy, cataplexy,sleep paralysis, hypnagogic hallucination, sleep arousal, insomnia, andnocturnal myoclonus.

In certain embodiments, the pharmaceutical compositions provided hereinare reduced in sodium content, which would render them particularlysuitable for the treatment of patients with hypertension, heart disease,or renal disease, or who are at risk of stroke.

In one aspect, provided herein are pharmaceutical compositionscomprising a mixture of salts of GHB, wherein the mixture comprises twoor more salts selected from the group consisting of a sodium salt ofhydroxybutyrate (Na.GHB), a potassium salt of gamma-hydroxybutyrate(K.GHB), a magnesium salt of gamma-hydroxybutyrate (Mg.(GHB)₂), and acalcium salt of gamma-hydroxybutyrate (Ca.(GHB)₂).

In certain embodiments, the pharmaceutical compositions comprise Na.GHB,K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certain embodiments, the Na.GHB saltis present in a wt/wt % of about 5% to about 10%, about 10% to about15%, about 15% to about 20%, about 20% to about 25%, about 25% to about30%, about 30% to about 35%, or about 35% to about 40%. In certainembodiments, the Na.GHB salt is present in a wt/wt % of about 5%, about10%, about 15%, about 20%, about 25%, about 30%, about 35%, or about40%. In certain embodiments, the K.GHB salt is present in a wt/wt % ofabout 10% to about 15%, about 15% to about 20%, about 20% to about 25%,about 25% to about 30%, about 30% to about 35%, or about 35% to about40%. In certain embodiments, the K.GHB salt is present in a wt/wt % ofabout 10%, about 15%, about 20%, about 25%, about 30%, about 35%, orabout 40%. In certain embodiments, the Mg.(GHB)₂ salt is present in awt/wt % of about 5% to about 10%, about 10% to about 15%, about 15% toabout 20%, about 20% to about 25%, or about 25% to about 30%. In certainembodiments, the Mg.(GHB)₂ salt is present in a wt/wt % of about 5%,about 10%, about 15%, about 20%, about 25%, or about 30%. In certainembodiments, the Ca.(GHB)₂ salt is present in a wt/wt % of about 20% toabout 25%, about 25% to about 30%, about 30% to about 35%, about 35% toabout 40%, about 40% to about 45%, about 45% to about 50%, about 50% toabout 55%, about 55% to about 60%, about 60% to about 65%, about 65% toabout 70%, about 70% to about 75%, or about 75% to about 80%. In certainembodiments, the Ca.(GHB)₂ salt is present in a wt/wt % of about 20%,about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about55%, about 60%, about 65%, about 70%, about 75%, or about 80%. Incertain embodiments, the Na.GHB salt is present in a wt/wt % of about 5%to about 40%, the K.GHB salt is present in a wt/wt % of about 10% toabout 40%, the Mg.(GHB)₂ salt is present in a wt/wt % of about 5% toabout 30%, and the Ca.(GHB)₂ salt is present in a wt/wt % of about 20%to about 80%. In certain embodiments, the Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂ salts are present in a wt/wt % ratio of about 8%:32%:20%:40%,respectively. In certain embodiments, the Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂ salts are present in a wt/wt % ratio of about 29%:31%:13%:27%,respectively. In certain embodiments, the Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂ salts are present in a wt/wt % ratio of about 8%:23%:21%:48%,respectively.

In certain embodiments, the pharmaceutical composition comprises amixture of any three of the salts selected from the group consisting ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂.

In certain embodiments, the pharmaceutical composition comprises Na.GHB,K.GHB, and Ca.(GHB)₂. In certain embodiments, the Na.GHB salt is presentin a wt/wt % of about 5% to about 40%, the K.GHB salt is present in awt/wt % of about 10% to about 40%, and the Ca.(GHB)₂ salt is present ina wt/wt % of about 20% to about 80%. In certain embodiments, the Na.GHB,K.GHB, and Ca.(GHB)₂ salts are present in a wt/wt % ratio of about11%:39%:50%, respectively.

In certain embodiments, the pharmaceutical composition comprises K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂. In certain embodiments, the K.GHB salt ispresent in a wt/wt % of about 10% to about 50%, the Mg.(GHB)₂ salt ispresent in a wt/wt % of about 20% to about 60%, and the Ca.(GHB)₂ saltis present in a wt/wt % of about 10% to about 40%. In certainembodiments, the K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂ salts are present in awt/wt % ratio of about 33%:42%:25%, respectively.

In certain embodiments, the pharmaceutical composition comprises anaqueous solution of about 500 mg/mL of the mixture of salts of GHB,wherein the composition has a pH of about 7.0 to about 9.0, wherein thecomposition is chemically stable and resistant to microbial growth, andwherein the composition is free of preservatives. In certainembodiments, the pharmaceutical composition has a pH of about 7.0, about7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7,about 7.8, about 7.9, about 8.0, about 8.1, about 8.2, about 8.3, about8.4, about 8.5, about 8.6, about 8.7, about 8.8, about 8.9, or about9.0. In certain embodiments, the composition has a pH of about 7.0 toabout 9.0, about 7.0 to about 8.5, about 7.3 to about 8.5, or about 7.5to about 9.0. In certain embodiments, the composition has a pH of about7.3 to about 8.5. In certain embodiments, the pharmaceutical compositionadditionally comprises a pH adjusting or buffering agent. In certainembodiments, the pH adjusting or buffering agent is an acid. In certainembodiments, the acid is an inorganic acid or an organic acid. Incertain embodiments, the acid is selected from the group consisting ofmalic acid, citric acid, acetic acid, boric acid, lactic acid,hydrochloric acid, phosphoric acid, sulfuric acid, sulfonic acid, andnitric acid. In certain embodiments, the acid is malic acid.

In certain embodiments, the pharmaceutical composition is formulated asa liquid formulation. In certain embodiments, the formulation ischemically stable and resistant to microbial growth, and is free ofpreservatives. In certain embodiments, the level of gamma-butyrolacetone(GBL) is 0.1% or less of the formulation. In certain embodiments, theformulation is suitable for oral administration. In certain embodiments,the formulation additionally comprises a flavoring agent. In certainembodiments, the formulation is administered in a single or multipledosage regimen.

In other aspects, provided herein are methods of treatment comprisingadministration of the pharmaceutical compositions or formulationsdisclosed herein.

In certain embodiments, the method treats cataplexy or daytimesleepiness in a patient who has been diagnosed with narcolepsy. Incertain embodiments, the method treats conditions responsive to GHB, forexample, fibromyalgia and sleep disorders such as apnea, sleep timedisturbances, narcolepsy, cataplexy, sleep paralysis, hypnagogichallucination, sleep arousal, insomnia, and nocturnal myoclonus. Incertain embodiments, the patient who has been diagnosed with narcolepsyhas also been diagnosed with hypertension, heart disease, renal disease,or is at risk of stroke.

In certain embodiments, the method comprises oral administration of theformulation in a multiple dosage regimen. In certain embodiments, themultiple dosage regimen comprises: (i) diluting an aqueous solutioncomprising about 500 mg/mL of the mixture of salts ofgamma-hydroxybutyrate with an aqueous medium to provide a first dose ofabout 2.25 to about 4.5 grams of the mixture of salts; (ii) diluting anaqueous solution comprising about 500 mg/mL of the mixture of salts ofgamma-hydroxybutyrate with an aqueous medium to provide a second dose ofabout 2.25 to about 4.5 grams of the mixture of salts; (iii) orallyadministering to a patient having narcolepsy the first dose within anhour prior to initial sleep onset; and (iv) orally administering to thepatient having narcolepsy the second dose within 2.5 to 4 hoursfollowing initial sleep onset.

In certain embodiments, the multiple dosage regimen comprises: (i)diluting an aqueous solution comprising about 500 mg/mL of the mixtureof salts of gamma-hydroxybutyrate with an aqueous medium to provide afirst dose of about 1.0 to about 4.5 grams of the mixture of salts; (ii)diluting an aqueous solution comprising about 500 mg/mL of the mixtureof salts of gamma-hydroxybutyrate with an aqueous medium to provide asecond dose of about 1.0 to about 4.5 grams of the mixture of salts;(iii) orally administering to a patient having narcolepsy the first dosewithin an hour prior to initial sleep onset; and (iv) orallyadministering to the patient having narcolepsy the second dose within2.5 to 4 hours following initial sleep onset.

In other aspects, provided herein are methods of making thepharmaceutical compositions disclosed herein.

In certain embodiments, the method of making comprises, for example,reacting GBL with one or more bases selected from the group consistingof sodium hydroxide, potassium hydroxide, magnesium hydroxide, andcalcium hydroxide. In certain embodiments, the reaction is carried outin a single vessel. In certain embodiments, the reaction is carried outin multiple vessels and the product is subsequently combined.

5. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 provides the results of the gastrointestinal motility study inCD-1 mice for Saline, Xyrem® solution (Sodium Oxybate), and saltMixtures A and G, which are disclosed in Examples 1 and 5, respectively.

6. DETAILED DESCRIPTION OF THE INVENTION

6.1 Definitions

As used herein, the term “gamma-hydroxybutyrate” (GHB) or “oxybate”refers to the negatively charged or anionic foal′ (conjugate base) ofgamma-hydroxybutyric acid. Without being limited by theory, GHB isbelieved to have the following structure:

As used herein, the term “gamma-hydroxybutyric acid” refers to theprotonated form (conjugate acid) of gamma-hydroxybutyrate. Without beinglimited by theory, gamma-hydroxybutyric acid is believed to have thefollowing structure:

As used herein, the terms “sodium gamma-hydroxybutyrate” (Na.GHB) or“sodium oxybate” (Na.oxybate) refers to the sodium salt form ofgamma-hydroxybutyric acid having the molecular weight of 126.09. Withoutbeing limited by any theory, Na.GHB is believed to have the followingstructure:

As used herein, the term “potassium gamma-hydroxybutyrate” (K.GHB) or“potassium oxybate” (K.oxybate) refers to the potassium salt foul ofgamma-hydroxybutyric acid having the molecular weight of 142.19. Withoutbeing limited by any theory, K.GHB is believed to have the followingstructure:

As used herein, the term “magnesium gamma-hydroxybutyrate” (Mg.(GHB)₂)or “magnesium oxybate” (Mg.oxybate) refers to the magnesium salt form ofgamma-hydroxybutyric acid having the molecular weight of 230.50. Withoutbeing limited by theory, Mg.(GHB)₂ is believed to have the followingstructure:

As used herein, the term “calcium gamma-hydroxybutyrate” (Ca.(GHB),) or“calcium oxybate” (Ca.oxybate) refers to the calcium salt foul ofgamma-hydroxybutyric acid having the molecular weight of 246.27. Withoutbeing limited by theory, Ca.(GHB)₂ is believed to have the followingstructure:

As used herein, the term “gamma-butyrolactone” (GBL) refers to acolorless oily liquid. Without being limited by theory, GBL is believedto have the following structure:

As used herein, the term “patient” refers to a mammal, particularly ahuman.

The terms “treat,” “treating” or “treatment,” as used herein, refer to amethod of alleviating or abrogating a disease and/or its attendantsymptoms.

As used herein, the term “about” or “approximately” means an acceptableerror for a particular value as determined by those skilled in the art,which depends in part on how the value is measured or determined. Incertain embodiments, the term “about” or “approximately” means within 1,2, 3, or 4 standard deviations. In certain embodiments, the term “about”or “approximately” means within 50%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%,4%, 3%, 2%, 1%, 0.5%, or 0.05% of a given value or range.

By “pharmaceutically acceptable” it is meant the active ingredient,cation, salt, diluent, excipient or carrier must be compatible with theother ingredients of the formulation and not unduly deleterious, forexample, that the active ingredient, cation, salt, diluent, excipient orcarrier does not produce an adverse, allergic or other untowardreaction, when administered to an animal, or a human, as appropriate.

The term “salt” or “salts,” as used herein, refers to a compound formedby the interaction of an acid and a base, the hydrogen atoms of the acidbeing replaced by the positive ion or cation of the base.Pharmaceutically acceptable salts, include inorganic acids such as, forexample, hydrochloric or phosphoric acids, or such organic acids asmalic, acetic, oxalic, tartaric, mandelic, and the like. Salts formedcan also be derived from inorganic bases such as, for example, sodium,potassium, silicates, ammonium, calcium, or ferric hydroxides, and suchorganic bases as isopropylamine, trimethylamine, histidine, procaine andthe like. In certain preferred embodiments, the salt is formed from aninorganic base that is a metal, for example, an alkali metal, such aslithium, potassium, sodium, or the like, an alkaline earth metal, suchas magnesium, calcium, barium, or the like, or aluminum or zinc. Othersalts may comprise ammonium. Alkali metals, such as lithium, potassium,sodium, and the like, may be used, preferably with an acid to form a pHadjusting agent. Examples of pharmaceutically acceptable base additionsalts include those derived from inorganic bases like sodium hydroxide,potassium hydroxide, magnesium hydroxide, calcium hydroxide, or ammoniumhydroxide, and the like (See, e.g, Berge et al., 1977, J. Pharm. Sci.66: 1).

As used herein, the terms “salt of GHB” or “salts of GHB,” as usedherein, refer to a compound formed by the interaction ofgamma-hydroxybutyric acid (the conjugate acid of GHB) with a base, forexample, NaOH, KOH, Mg(OH)₂, and Ca(OH)₂, and the like, the hydrogenatoms of the acid being replaced by the positive ion or cation of thebase. Such salts may include, for example, Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂, and the like. It will be understood by those skilled in theart that such salts may be in solid form, or such salts may be inpartially or fully solvated form, for example, as when dissolved in anaqueous medium. It will be further understood by those skilled in theart, that, depending on the solubility of the salt in the aqueousmedium, that the salt may be present in the aqueous medium as solvatedcation(s) and anion(s), or as a precipitated solid, as illustrated belowfor the solubility equilibrium of Ca.(GHB)₂:

The terms “mixture of salts” or “salt mixture,” as used herein, refersto salts of GHB where two or more different cations are present incombination with each other in a composition. Such mixtures of salts mayinclude, for example, two or more salts selected from the groupconsisting of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂.

The term “wt/wt %,” are used herein, refers to the normalized weightpercent of a particular salt in a salt mixture. A sample calculation ofwt/wt % is provided in Example 1 of the present disclosure.

The term “wt/wt % ratio,” as used herein, refers to the ratio of wt/wt %values in a mixture of salt. For example, where the salts Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂ are present in a wt/wt %'s of 8%, 32%, 20% and40%, respectively, the wt/wt % ratio of Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂ in the mixture is 8%:32%:20%:40%.

The term, “buffering agent,” as used herein, refers to a weak acid orbase used to maintain the pH of a solution near a chosen pH value afterthe addition of another acidic or basic compound. The function of suchan agent is to prevent the change in pH when acids or bases are added toa solution. Such agents may be acids, bases, or combinations thereof.

The term, “adjusting agent,” as used herein, refers to an acid or baseused to alter the pH of a solution to a chosen pH value. The function ofsuch an agent is to alter the pH of a solution to the desired valuesubsequent to the addition of acidic or basic compounds.

The term, “acid,” as used herein, refers to a substance which accepts ashare in a pair of electrons. Such substances include malic acid, citricacid, acetic acid, boric acid, lactic acid, hydrochloric acid,phosphoric acid, sulfuric acid, sulfonic acid, nitric acid, and thelike.

The term, “base,” as used herein, refers to a substance which shares apair of electrons. Such substances include sodium hydroxide, potassiumhydroxide, magnesium hydroxide, calcium hydroxide, and the like.

The term, “chemically stable,” as used herein, refers to a chemicalcompound which is not particularly reactive in a specific environmentand retains its useful properties on a timescale of its expectedusefulness. Specifically, the usefulness of the compound is maintainedin the presence of air, moisture, or heat. Conversely, the compoundlacks chemical stability if it decomposes under the conditions of aspecific environment. As used herein in certain embodiments, “chemicallystable” may mean resistant to degradation of GHB into its known orunknown decomposition elements. The level of GBL that is acceptable canbe up to 0.15% of the formulation as per the ICH guidelines forshelf-life determination.

The term, “microbial,” as used herein, refers to a microscopic organismthat comprises either a single cell, cell cluster or multicellularorganism.

The term “resistant to microbial growth” or “resistant to microbialchallenge,” as used herein, means that the compositions or formulationsmeet the criteria set by the Food and Drug Administration and the U.S.Pharmacopoeia for products made with aqueous bases or vehicles, whichfor bacteria means not less than a 1.0 log reduction from the initialcount at 14 days, and no increase from the 14 days count at 28 days, andfor yeast and molds, no increase from the initial calculated count at 14and 28 days.

The term, “preservative,” as used herein, refers to a naturallyoccurring or synthetically produced substance which can be added tofood, pharmaceuticals, paints, biological samples, wood, etc. to preventdecomposition by microbial growth or by chemical decomposition.

The term, “formulation,” as used herein, refers to a stable andpharmaceutically acceptable preparation of a pharmaceutical compositiondisclosed herein.

The term, “liquid formulation,” as used herein, refers to a water-basedformulation, in particular, a formulation that is an aqueous solution.

The term, “cataplexy,” as used herein, refers to a condition where apatient exhibits a sudden and transient loss of muscle tone, oftentriggered by emotions.

The term, “daytime sleepiness,” as used herein, refers to a conditionwhere a patient exhibits persistent sleepiness, and often a general lackof energy, even after apparent adequate night time sleep.

The term, “narcolepsy,” as used herein, refers to a chronic sleepdisorder characterized by excessive sleepiness and sleep attacks atinappropriate times.

The term, “apnea,” as used herein, refers to a condition where a patientsuspends external breathing.

The term, “sleep time disturbances,” as used herein, refers to acondition where a patient exhibits abnormal sleep patterns. Sleep timedisturbances can be serious enough to interfere with normal physical,mental and emotional functioning.

The term, “sleep paralysis,” as used herein, refers to a condition inwhich a patient who is falling asleep or awakening form sleep experiencean inability to move. It is a transition state between wakefulness andrest characterized by complete muscle weakness.

The term, “hypnagogic hallucination,” as used herein, refers to atransition state between wakefulness and sleep where a patientexperiences vivid hallucinations.

The term, “sleep arousal,” as used herein, refers to a condition where apatient engages in sexual acts while still asleep.

The term, “insomnia,” as used herein, refers to a condition where apatient has difficulties falling asleep and maintaining sleep.

The term, “nocturnal myoclonus,” as used herein, refers to a conditionwhere a patient has repetitive movement of the limbs during sleep oreven wakefulness which is sometimes confused with a seizure.

The term “flavoring” or “flavoring agent,” as used herein, refers to asubstance that alters the flavor of the composition during oralconsumption. A type of “flavoring agent” would be a sweetener.

The term “coloring” or “coloring agent,” as used herein, refers to asubstance that alters the color of the composition.

6.2 Embodiments of the Invention

6.2.1 Pharmaceutical Compositions Comprising Salt Mixtures of GHB

In certain aspects, provided herein are pharmaceutical compositionscomprising gamma-hydroxybutyrate (GHB) and one or more pharmaceuticallyacceptable cations of an alkali metal or an alkaline earth metal. Asused herein, “alkali metal” means any of the elements found in Group IAof the periodic table, including, for example, lithium, sodium, andpotassium. As used herein, “alkaline earth metal” means any of theelements found in Group II of the periodic table, including, forexample, magnesium and calcium.

In certain embodiments, the pharmaceutical compositions comprise GHB andmore than one pharmaceutically acceptable cations of an alkali metal oran alkaline earth metal.

In certain embodiments, the pharmaceutical compositions comprise GHB andmore than one cation selected from the group consisting of Na⁺, K⁺,Mg⁺², and Ca⁺². In certain embodiments, the pharmaceutical compositionscomprise GHB and two or more cations selected from the group consistingof Na⁺, K⁺, Mg⁺², and Ca⁺². In certain embodiments, the pharmaceuticalcompositions comprise GHB and three or more cations selected from thegroup consisting of Na⁺, K⁺, Mg⁺², and Ca⁺². In certain embodiments, thepharmaceutical compositions comprise GHB and all four cations selectedfrom the group consisting of Na⁺, K⁺, Mg⁺², and Ca⁺². In certainembodiments, the pharmaceutical compositions comprise GHB and more thanone cation selected from the group consisting of K⁺, Mg⁺², and Ca⁺². Incertain embodiments, the pharmaceutical compositions comprise GHB andall three cations selected from the group consisting of K⁺, Mg⁺², andCa⁺². In certain embodiments, the pharmaceutical compositions do notcomprise the cation Na⁺, so as to minimize the undesirable side effectsof the sodium, particularly in patients with hypertension, heartdisease, renal disease or at risk of stroke. In certain embodiments, thepharmaceutical compositions do not comprise the cation Na⁺, so as toimprove the taste of the compositions.

In certain aspects, provided herein are pharmaceutical compositionscomprising salts of GHB. As used herein, the term “salt of GHB” or“salts of GHB” is used interchangeably with the term “cation.” Forexample, a pharmaceutical composition comprising GHB and the fourcations Na⁺, K⁺, Mg⁺², and Ca⁺² will be understood by those skilled inthe art to also mean a pharmaceutical composition comprising the saltsNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. It will be also understood bythose skilled in the art that such salts may be in solid form, or may bein partially or fully solvated form, for example, as when dissolved inan aqueous medium. It will be further understood by those skilled in theart, that, depending on the solubility of the salt in the aqueousmedium, that the salt may be present in the aqueous medium as solvatedcation(s) and anion(s), or as a precipitated solid.

In certain embodiments, the pharmaceutical compositions comprise morethan one salt selected from the group consisting of a sodium salt ofhydroxybutyrate (Na.GHB), a potassium salt of gamma-hydroxybutyrate(K.GHB), a magnesium salt of gamma-hydroxybutyrate (Mg.(GHB)₂), and acalcium salt of gamma-hydroxybutyrate (Ca.(GHB)₂). In certainembodiments, the pharmaceutical compositions comprise two or more saltsselected from the group consisting of Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂. In certain embodiments, the pharmaceutical compositionscomprise three or more salts selected from the group consisting ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certain embodiments, thepharmaceutical compositions comprise all four salts selected from thegroup consisting of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certainembodiments, the pharmaceutical compositions comprise more than one saltselected from the group consisting of K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂.In certain embodiments, the pharmaceutical compositions comprise allthree salts selected from the group consisting of K.GHB, Mg.(GHB)₂, andCa.(GHB)₂. In certain embodiments, the pharmaceutical compositions donot comprise the salt Na.GHB, so as to minimize the undesirable sideeffects of the sodium, particularly in patients with hypertension, heartdisease, renal disease or at risk of stroke.

In certain embodiments, the pharmaceutical compositions comprise amixture of more than one salt selected from the group consisting ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certain embodiments, thepharmaceutical compositions comprise a mixture or two or more saltsselected from the group consisting of Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂. In certain embodiments, the pharmaceutical compositionscomprise a mixture of three or more salts selected from the groupconsisting of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certainembodiments, the pharmaceutical composition comprises a mixture of thefour salts Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certainembodiments, the mixture of salts does not comprise the salt Na.GHB.

In certain embodiments, the pharmaceutical composition comprises amixture of any three of the salts selected from the group consisting ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certain embodiments, thepharmaceutical composition comprises K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. Incertain embodiments, the pharmaceutical composition comprises Na.GHB,Mg.(GHB)₂, and Ca.(GHB)₂. In certain embodiments, the pharmaceuticalcomposition comprises Na.GHB, K.GHB, and Ca.(GHB)₂. In certainembodiments, the pharmaceutical composition comprises Na.GHB, K.GHB, andMg.(GHB)₂.

In certain embodiments, the pharmaceutical composition comprises amixture of any two of the salts selected from the group consisting ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. In certain embodiments, thepharmaceutical composition comprises Na.GHB and K.GHB. In certainembodiments, the pharmaceutical composition comprises Na.GHB andMg.(GHB)₂. In certain embodiments, the pharmaceutical compositioncomprises Na.GHB and Ca.(GHB)₂. In certain embodiments, thepharmaceutical composition comprises K.GHB and Mg.(GHB)₂. In certainembodiments, the pharmaceutical composition comprises K.GHB andCa.(GHB)₂. In certain embodiments, the pharmaceutical compositioncomprises Mg.(GHB)₂ and Ca.(GHB)₂.

6.2.2 Weight/Weight and Molar Equivalents Percents

In certain embodiments, the pharmaceutical composition comprises varyingweight/weight percentages (wt/wt %) of Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂.

In certain embodiments, the Na.GHB salt is present in a wt/wt % of about1% to about 5%, about 5% to about 10%, about 10% to about 15%, about 15%to about 20%, about 20% to about 25%, about 25% to about 30%, about 30%to about 35%, or about 35% to about 40%, about 40% to about 45%, about45% to about 50%, about 50% to about 55%, about 55% to about 60%, about60% to about 65%, about 65% to about 70%, about 70% to about 75%, about75% to about 80%, about 80% to about 85%, about 85% to about 90%, about90% to about 95%, or about 95% to about 100%. In certain embodiments,the Na.GHB salt is present in a wt/wt % of about 1%, about 5%, about10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%,about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about75%, about 80%, about 85%, about 90%, about 95%, or about 100%. Incertain embodiments, the Na.GHB salt is absent.

In certain embodiments, the K.GHB salt is present in a wt/wt % of about1% to about 5%, about 5% to about 10%, about 10% to about 15%, about 15%to about 20%, about 20% to about 25%, about 25% to about 30%, about 30%to about 35%, or about 35% to about 40%, about 40% to about 45%, about45% to about 50%, about 50% to about 55%, about 55% to about 60%, about60% to about 65%, about 65% to about 70%, about 70% to about 75%, about75% to about 80%, about 80% to about 85%, about 85% to about 90%, about90% to about 95%, or about 95% to about 100%. In certain embodiments,the K.GHB salt is present in a wt/wt % of about 1%, about 5%, about 10%,about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%,about 80%, about 85%, about 90%, about 95%, or about 100%. In certainembodiments, the K.GHB salt is absent.

In certain embodiments, the Mg.(GHB)₂ salt is present in a wt/wt % ofabout 1% to about 5%, about 5% to about 10%, about 10% to about 15%,about 15% to about 20%, about 20% to about 25%, about 25% to about 30%,about 30% to about 35%, or about 35% to about 40%, about 40% to about45%, about 45% to about 50%, about 50% to about 55%, about 55% to about60%, about 60% to about 65%, about 65% to about 70%, about 70% to about75%, about 75% to about 80%, about 80% to about 85%, about 85% to about90%, about 90% to about 95%, or about 95% to about 100%. In certainembodiments, the Mg.(GHB)₂ salt is present in a wt/wt % of about 1%,about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%,about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, orabout 100%. In certain embodiments, the Mg.(GHB)₂ salt is absent.

In certain embodiments, the Ca.(GHB)₂ salt is present in a wt/wt % ofabout 1% to about 5%, about 5% to about 10%, about 10% to about 15%,about 15% to about 20%, about 20% to about 25%, about 25% to about 30%,about 30% to about 35%, or about 35% to about 40%, about 40% to about45%, about 45% to about 50%, about 50% to about 55%, about 55% to about60%, about 60% to about 65%, about 65% to about 70%, about 70% to about75%, about 75% to about 80%, about 80% to about 85%, about 85% to about90%, about 90% to about 95%, or about 95% to about 100%. In certainembodiments, the Ca.(GHB)₂ salt is present in a wt/wt % of about 1%,about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%,about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, orabout 100%. In certain embodiments, the Ca.(GHB)₂ salt is absent.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB salt ispresent in a wt/wt % of about 5% to about 10%, about 10% to about 15%,about 15% to about 20%, about 20% to about 25%, about 25% to about 30%,about 30% to about 35%, or about 35% to about 40%. In certainembodiments, where the pharmaceutical composition comprises a mixture ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB salt is present in awt/wt % of about 5%, about 10%, about 15%, about 20%, about 25%, about30%, about 35%, or about 40%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB salt ispresent in a wt/wt % of about 10% to about 15%, about 15% to about 20%,about 20% to about 25%, about 25% to about 30%, about 30% to about 35%,or about 35% to about 40%. In certain embodiments, where thepharmaceutical composition comprises a mixture of Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB salt is present in a wt/wt % ofabout 10%, about 15%, about 20%, about 25%, about 30%, about 35%, orabout 40%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Mg.(GHB)₂ saltis present in a wt/wt % of about 5% to about 10%, about 10% to about15%, about 15% to about 20%, about 20% to about 25%, or about 25% toabout 30%. In certain embodiments, where the pharmaceutical compositioncomprises a mixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, theMg.(GHB)₂ salt is present in a wt/wt % of about 5%, about 10%, about15%, about 20%, about 25%, or about 30%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, it is contemplatedthat the Mg.(GHB)₂ salt may be present in a wt/wt % of about 30% toabout 40%, or about 40% to about 50%, or even higher. In certainembodiments, where the pharmaceutical composition comprises a mixture ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, it is contemplated that theMg.(GHB)₂ salt may be present in a wt/wt % or about 35%, about 40%, orabout 45%, about 50%, or even higher.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Ca.(GHB)₂ saltis present in a wt/wt % of about 20% to about 25%, about 25% to about30%, about 30% to about 35%, about 35% to about 40%, about 40% to about45%, about 45% to about 50%, about 50% to about 55%, about 55% to about60%, about 60% to about 65%, about 65% to about 70%, about 70% to about75%, or about 70% to about 80%. In certain embodiments, where thepharmaceutical composition comprises a mixture of Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂, the Ca.(GHB)₂ salt is present in a wt/wt % ofabout 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about50%, about 55%, about 60%, about 65%, about 70%, about 75%, or about80%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB salt ispresent in a wt/wt % of about 5% to about 40%, the K.GHB salt is presentin a wt/wt % of about 10% to about 40%, the Mg.(GHB)₂ salt is present ina wt/wt % of about 5% to about 30%, and the Ca.(GHB)₂ salt is present ina wt/wt % of about 20% to about 80%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂ salts are present in a wt/wt % ratio of about8%:32%:20%:40%, respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂ salts are present in a wt/wt % ratio of about29%:31%:13%:27%, respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB), salts are present in a wt/wt % ratio of about8%:23%:21%:48%, respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, and Ca.(GHB)₂, the Na.GHB salt is present in awt/wt % of about 5% to about 40%, the K.GHB salt is present in a wt/wt %of about 10% to about 40%, and the Ca.(GHB)₂ salt is present in a wt/wt% of about 20% to about 80%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, and Ca.(GHB)₂, the Na.GHB salt is present in awt/wt % of about 5% to about 40%, the K.GHB salt is present in a wt/wt %of about 20% to about 40%, and the Ca.(GHB)₂ salt is present in a wt/wt% of about 20% to about 60%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, and Ca.(GHB)₂, the Na.GHB, K.GHB, andCa.(GHB)₂ salts are present in a wt/wt % ratio of about 11%:39%:50%,respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB salt is present ina wt/wt % of about 10% to about 50%, the Mg.(GHB)₂ salt is present in awt/wt % of about 20% to about 60%, and the Ca.(GHB)₂ salt is present ina wt/wt % of about 10% to about 40%.

In certain embodiments, the K.GHB salt is present in a wt/wt % of about10% to about 50%, the Mg.(GHB)₂ salt is present in a wt/wt % of about20% to about 60%, and the Ca.(GHB)₂ salt is present in a wt/wt % ofabout 10% to about 40%.

In certain embodiments, where the pharmaceutical composition comprises amixture of K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB, Mg.(GHB)₂, andCa.(GHB)₂ salts are present in a wt/wt % ratio of about 33%:42%:25%,respectively.

In certain embodiments, the pharmaceutical compositions comprise varyingpercents of oxybate, expressed as % molar equivalents (% mol. equiv.) ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂. The terms “% molar equivalents”and “% mol. equiv.,” as used herein, refer to molar composition of saltsexpressed as a percent of GHB equivalents. Those skilled in the art willunderstand that as each GHB unit is considered to be one molarequivalent, the monovalent cations, Na⁺ and K⁺, have one molarequivalent per salt, and the divalent cations, Mg⁺² and Ca⁺², have twomolar equivalents per salt. A sample calculation of % mol. equiv. isprovided in Example 1 of the present disclosure.

In certain embodiments, the Na.GHB salt is present in a % mol. equiv. ofabout 1% to about 5%, about 5% to about 10%, about 10% to about 15%,about 15% to about 20%, about 20% to about 25%, about 25% to about 30%,about 30% to about 35%, or about 35% to about 40%, about 40% to about45%, about 45% to about 50%, about 50% to about 55%, about 55% to about60%, about 60% to about 65%, about 65% to about 70%, about 70% to about75%, about 75% to about 80%, about 80% to about 85%, about 85% to about90%, about 90% to about 95%, or about 95% to about 100%. In certainembodiments, the Na.GHB salt is present in a % mol. equiv. of about 1%,about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%,about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, orabout 100%.

In certain embodiments, the K.GHB salt is present in a % mol. equiv. ofabout 1% to about 5%, about 5% to about 10%, about 10% to about 15%,about 15% to about 20%, about 20% to about 25%, about 25% to about 30%,about 30% to about 35%, or about 35% to about 40%, about 40% to about45%, about 45% to about 50%, about 50% to about 55%, about 55% to about60%, about 60% to about 65%, about 65% to about 70%, about 70% to about75%, about 75% to about 80%, about 80% to about 85%, about 85% to about90%, about 90% to about 95%, or about 95% to about 100%. In certainembodiments, the K.GHB salt is present in a % mol. equiv. of about 1%,about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%,about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, orabout 100%.

In certain embodiments, the Mg.(GHB)₂ salt is present in a % mol. equiv.of about 1% to about 5%, about 5% to about 10%, about 10% to about 15%,about 15% to about 20%, about 20% to about 25%, about 25% to about 30%,about 30% to about 35%, or about 35% to about 40%, about 40% to about45%, about 45% to about 50%, about 50% to about 55%, about 55% to about60%, about 60% to about 65%, about 65% to about 70%, about 70% to about75%, about 75% to about 80%, about 80% to about 85%, about 85% to about90%, about 90% to about 95%, or about 95% to about 100%. In certainembodiments, the Mg.(GHB)₂ salt is present in a % mol. equiv. of about1%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%,or about 100%.

In certain embodiments, the Ca.(GHB)₂ salt is present in a % mol. equiv.of about 1% to about 5%, about 5% to about 10%, about 10% to about 15%,about 15% to about 20%, about 20% to about 25%, about 25% to about 30%,about 30% to about 35%, or about 35% to about 40%, about 40% to about45%, about 45% to about 50%, about 50% to about 55%, about 55% to about60%, about 60% to about 65%, about 65% to about 70%, about 70% to about75%, about 75% to about 80%, about 80% to about 85%, about 85% to about90%, about 90% to about 95%, or about 95% to about 100%. In certainembodiments, the Ca.(GHB)₂ salt is present in a % mol. equiv. of about1%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%,or about 100%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB salt ispresent in a % mol. equiv. of about 5% to about 10%, about 10% to about15%, about 15% to about 20%, about 20% to about 25%, about 25% to about30%, about 30% to about 35%, or about 35% to about 40%. In certainembodiments, where the pharmaceutical composition comprises a mixture ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB salt is present in a% mol. equiv. of about 5%, about 10%, about 15%, about 20%, about 25%,about 30%, about 35%, or about 40%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB salt ispresent in a % mol. equiv. of about 10% to about 15%, about 15% to about20%, about 20% to about 25%, about 25% to about 30%, about 30% to about35%, or about 35% to about 40%. In certain embodiments, where thepharmaceutical composition comprises a mixture of Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB salt is present in a % mol. equiv.of about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, orabout 40%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Mg.(GHB)₂ saltis present in a % mol. equiv. of about 5% to about 10%, about 10% toabout 15%, about 15% to about 20%, about 20% to about 25%, or about 25%to about 30%. In certain embodiments, where the pharmaceuticalcomposition comprises a mixture of Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂, the Mg.(GHB)₂ salt is present in a % mol. equiv. of about 5%,about 10%, about 15%, about 20%, about 25%, or about 30%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, it is contemplatedthat the Mg.(GHB)₂ salt may be present in a % mol. equiv. of about 30%to about 40%, or about 40% to about 50%, or even higher. In certainembodiments, where the pharmaceutical composition comprises a mixture ofNa.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, it is contemplated that theMg.(GHB)₂ salt may be present in a % mol. equiv. of about 35%, about40%, about 45%, or about 50%, or even higher.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Ca.(GHB)₂ saltis present in a % mol. equiv. of about 20% to about 25%, about 25% toabout 30%, about 30% to about 35%, about 35% to about 40%, about 40% toabout 45%, about 45% to about 50%, about 50% to about 55%, about 55% toabout 60%, about 60% to about 65%, about 65% to about 70%, about 70% toabout 75%, or about 75% to about 80%. In certain embodiments, where thepharmaceutical composition comprises a mixture of Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂, the Ca.(GHB)₂ salt is present in a % mol.equiv. of about 20%, about 25%, about 30%, about 35%, about 40%, about45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%,or about 80%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB salt ispresent in a % mol. equiv. of about 5% to about 40%, the K.GHB salt ispresent in a % mol. equiv. of about 10% to about 40%, the Mg.(GHB)₂ saltis present in a % mol. equiv. of about 5% to about 30%, and theCa.(GHB)₂ salt is present in a % mol. equiv. of about 20% to about 80%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂ salts are present in a % mol. equiv. ratio ofabout 8%:28%:22%:41%, respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂ salts are present in a % mol. equiv. ratio ofabout 29%:28%:15%:28%, respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂ salts are present in a % mol. equiv. ratio ofabout 8%:23%:21%:48%, respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, and Ca.(GHB)₂, the Na.GHB salt is present in a% mol. equiv. of about 5% to about 40%, the K.GHB salt is present in a %mol. equiv. of about 10% to about 40%, and the Ca.(GHB)₂ salt is presentin a % mol. equiv. of about 20% to about 80%.

In certain embodiments, where the pharmaceutical composition comprises amixture of Na.GHB, K.GHB, and Ca.(GHB)₂, the Na.GHB, K.GHB, andCa.(GHB)₂ salts are present in a % mol. equiv. ratio of about11%:36%:53%, respectively.

In certain embodiments, where the pharmaceutical composition comprises amixture of K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB salt is present ina % mol. equiv. of about 10% to about 50%, the Mg.(GHB)₂ salt is presentin a % mol. equiv. of about 20% to about 60%, and the Ca.(GHB)₂ salt ispresent in a % mol. equiv. of about 10% to about 40%.

In certain embodiments, where the pharmaceutical composition comprises amixture of K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂, the K.GHB, Mg.(GHB)₂, andCa.(GHB)₂ salts are present in a % mol. equiv. ratio of about33%:42%:25%, respectively.

6.2.3 Concentrations and pH's

In certain embodiments, the pharmaceutical composition comprises anaqueous solution.

In certain embodiments, the concentration of the mixture of salts of GHBin the solution is about 100 to about 150 mg/mL, about 150 to about 200mg/mL, about 200 to about 250 mg/mL, about 250 to about 300 mg/mL, about300 to about 350 mg/mL, about about 350 to about 400 mg/mL, about 400 toabout 450 mg/mL, about 450 to about 500 mg/mL, about 500 to about 550mg/mL, about 550 to about 600 mg/mL, about 600 to about 650 mg/mL, about650 to about 700 mg/mL, about 700 to about 750 mg/mL, about 750 to about800 mg/mL, about 800 to about 850 mg/mL, or about 850 to about 900mg/mL. In certain embodiments, the concentration of the mixture of saltsof GHB in the solution is about 250 mg/mL to about 750 mg/mL. In certainembodiments, the concentration of the mixture of salts of GHB in thesolution is about 150 mg/mL, about 200 mg/mL, about 250 mg/mL, about 300mg/mL, about 350 mg/mL, about 400 mg/mL, about 450 mg/mL, about 500mg/mL, about 550 mg/mL, about 600 mg/mL, about 650 mg/mL, about 700mg/mL, about 750 mg/mL, about 800 mg/mL, about 850 mg/mL, or about 900mg/mL. In certain embodiments, the concentration of the mixture of saltsof GHB in the solution is about 500 mg/mL.

It will be understood that the maximum solubility of GHB is affected bythe pH of the aqueous medium. For example, at about pH 4, the maximumamount of Na.GHB that can be dissolved is about 450 mg/ml. The value ofpH that is conducive to GHB solubility increases so that the minimal pHthat will dissolve 750 mg/ml GHB was found to be about pH 6.8.

Accordingly, in certain embodiments, the composition has a pH of about3.5 to about 4.0, about 4.0 to about 4.5, about 4.5 to about 5.0, about5.5 to about 6.0, about 6.0 to about 6.5, about 6.5 to about 7.0, about7.0 to about 7.5, about 7.5 to about 8.0, about 8.0 to about 8.5, orabout 8.5 to about 9.0. In certain embodiments, the composition has a pHof about 3.5, about 4.0, about 4.5, about 5.0, about 5.5, about 6.0,about 6.5, about 7.0, about 7.5, about 8.0, about 8.5, or about 9.0. Incertain embodiments, the composition has a pH of about 7.0 to about 9.0,about 7.0 to about 8.5, about 7.3 to about 8.5, or about 7.5 to about9.0. In certain embodiments, the composition has a pH of about 7.3 toabout 8.5.

In certain embodiments, the composition is chemically stable andresistant to microbial growth. In certain embodiments, the compositionis free of preservatives.

It will also be understood that the pH of the aqueous solution affectsthe resistance of the composition to microbial growth at about 500 mg/mlGHB. For example, Na.GHB at this concentration in an aqueous medium thatis between about pH 5 and pH 9 is resistant to microbial growth, withcompositions at about pH 6 to about pH 7.5 being particularly resistantto microbial growth. However, at concentrations of GHB greater thanabout 750 mg/ml above about pH 7.5, the resistance to microbial growthis reduced.

It will be further understood that the concentration of GHB in thecomposition, when evaluated in relationship to the pH, affects theresistance of the GHB composition to microbial challenge. For example,compositions of Na.GHB at or below 150 mg/ml are poorly resistant tomicrobial challenge from a pH range of about pH 3 to about pH 9.However, concentrations of Na.GHB of greater than about 150 mg/ml, up toabout 1000 mg/ml of GHB, are believed to be suitably resistant tomicrobial contamination at these pH ranges.

It will be further understood that the chemical stability of GHB isaffected by pH. Accordingly, the method for preparing GHB, as describedherein, particularly as disclosed in the specific examples, varies withpH. GBL begins to form if the pH is about 6 or less. Compositions with apH of greater than about 6.0 are preferred to produce chemically stableformulations of GHB. Thus, a preferred range to produce chemicallystable GHB would be from about pH 6 to about pH 9. However, any pH orrange of pH values where a clinically acceptable amount of GBL isproduced is also contemplated as being preferred, and is encompassed bythe present invention. The range of GBL could be regulatorily broadenedwith availability of sufficient toxicological data.

In certain embodiments, a pH adjusting or buffering agent may be addedto the composition. The choice of a pH adjusting or buffering agent mayaffect the resistance to microbial challenge and/or the stability ofGHB, as measured by the reduction in assayable GHB. Compositions of GHB,pH adjusted or buffered with malic acid are resistant to both microbialgrowth and chemical degradation of GHB, and are preferred. Other pHadjusting or buffering agents may be selected. Agents that adjust pHthat are selected on this basis will undergo a taste testing study.However, any pH adjusting or buffering agent disclosed herein or aswould be known to those skilled in the art is contemplated as beinguseful from the compositions or formulations disclosed herein. Ofcourse, any salt, flavoring agent, excipient, or other pharmaceuticallyacceptable addition described herein or as would be known to thoseskilled in the art is contemplated as being useful for the compositionsor formulations disclosed herein.

In certain embodiments, the pH adjusting or buffering agent is an acid.In certain embodiments, the pH adjusting or buffering agent is aninorganic acid or an organic acid. In certain embodiments, the pHadjusting or buffering agent is selected from the group consisting ofmalic acid, citric acid, acetic acid, boric acid, lactic acid,hydrochloric acid, phosphoric acid, sulfuric acid, sulfonic acid, andnitric acid. In certain embodiments, the pH adjusting or buffering agentis malic acid.

The aqueous solutions disclosed herein typically comprise an effectiveamount of GHB, which may be dissolved or dispersed in a pharmaceuticallyacceptable carrier and/or an aqueous medium.

As used herein, “pharmaceutically acceptable carrier” includes any andall solvents, dispersion media, coatings, antibacterial and antifungalagents, isotonic and absorption delaying agents and the like. The use ofsuch media and agents for pharmaceutical active substances is well knownin the art. Insofar as any conventional media or agent is incompatiblewith the active ingredient, its use in the therapeutic compositions isnot appropriate. Supplementary compatible active ingredients can beincorporated into the compositions. For human administration,preparations should meet sterility, pyrogenicity, general safety andpurity standards as required by the Food and Drug Administration (FDA).

6.2.4 Formulations

In certain embodiments, the compositions disclosed herein are providedin a formulation, preferably, a liquid formulation, although solidformulations are also contemplated.

In certain embodiments, the formulation is chemically stable andresistant to microbial growth. In certain embodiments, the formulationis free of preservatives. In certain embodiments, the level ofgamma-butyrolacetone (GBL) is 0.1% or less of the formulation.

In certain embodiments, the formulation is suitable for oraladministration.

In certain embodiments, the formulation additionally comprises aflavoring agent. Preferred sweeteners or flavoring agents would bemicrobially non-metabolizable. Especially preferred sweeteners orflavoring agents would be carbohydrates such as xylitol and sorbitol.Such flavoring agents include, but are not limited to, acacia syrup,anethole, anise oil, aromatic elixir, benzaldehyde, benzaldehydeelixir-compound, caraway, caraway oil, cardamom oil, cardamom seed,cardamom spirit, cardamom tincture-compound, cherry juice, cherry syrup,cinnamon, cinnamon oil, cinnamon water, citric acid, citric acid syrup,clove oil, coca, coca syrup, coriander oil, dextrose, eriodictyon,eriodictyon fluidextract, eriodictyon syrup-aromatic, ethyl acetate,ethyl, vanillin, fennel oil, ginger, ginger fluidextract, gingeroleoresin, glucose, glycerin, glycyrrhiza, glycyrrhiza elixir,glycyrrhiza extract, glycyrrhiza extract-pure, glycyrrhiza fluidextract,glycyrrhiza syrup, honey, non-alcoholic elixir, lavender oil, citrusextract or oil, lemon oil, lemon tincture, mannitol, methyl salicylate,nutmeg oil, orange-bitter-elixir, orange-bitter-oil, orange flower oil,orange flower water, orange oil, orange peel-bitter,orange-peel-sweet-tincture, orange spirit-compound, compound, orangesyrup, peppermint, peppermint oil, peppermint spirit, peppermint water,phenylethyl alcohol, raspberry juice, raspberry syrup, rosemary oil,rose oil, rose water, saccharin, saccharin calcium, saccharin sodium,sarsaparilla syrup, sorbitol solution, spearmint, spearmint oil,sucralose, sucrose, syrup, thyme oil, tolu balsam, tolu balsam syrup,vanilla, vanilla tincture, vanillin or wild cherry syrup.

In certain embodiments, the formulation additionally comprises acoloring agent. Preferred coloring agents would be microbiallynon-metabolizable.

In certain embodiments, the formulation is administered in a single ormultiple dosage regimen.

Any of the above formulations may be prepared and/or packaged as apowdered or dry form for mixing with an aqueous medium before oraladministration, or they may be prepared in an aqueous medium andpackaged. After mixing with an aqueous medium, preferably to prepare asolution, these formulations are resistant to both microbial growth andchemical conversion of GHB to GBL, thereby increasing the shelf-life oftherapeutic formulations of GHB in an aqueous medium. These formulationsthen provide an easily titratable liquid medium for measuring the dosageof GHB to be administered to a patient. Additional embodiments of thecomposition and methods of preparation are described below and in theexamples.

The GHB may be lyophilized for more ready formulation into a desiredvehicle or medium where appropriate. The active compounds may beformulated for parenteral administration, e.g., formulated for injectionvia intravenous, intraarterial, intramuscular, sub-cutaneous,intralesional, intraperitoneal or other parenteral routes. Thepreparation of a composition that comprises an aqueous solution thatcontains a GHB agent as an active component or ingredient will be knownto those of skill in the art in light of the present disclosure.Typically, such compositions can be prepared as injectables, either asliquid solutions or suspensions. Solid forms suitable for using toprepare solutions or suspensions upon the addition of a liquid prior toinjection can also be prepared; and the preparations can also beemulsified.

The pharmaceutical forms suitable for injectable use include sterileaqueous solutions or dispersions; formulations including, e.g., aqueouspropylene glycol; and sterile powders for the extemporaneous preparationof sterile injectable solutions or dispersions. In all cases the formmust be sterile and must be fluid to the extent that easy syringabilityexists. It must be stable under the conditions of manufacture andstorage and must be preserved against the contaminating action ofmicroorganisms, such as bacteria and fungi.

Solutions of the active compounds as free acid or pharmacologicallyacceptable salts can be prepared in water suitably mixed withhydroxypropylcellulose and/or a pharmaceutically acceptable surfactant.Dispersions can also be prepared in glycerol, liquid polyethyleneglycols, and mixtures thereof as well as in oils. Under ordinaryconditions of storage and use, these preparation may best contain apreservative to further prevent the growth of microorganisms.

The carrier can also be a solvent or dispersion medium containing, forexample, water, ethanol, polyol (for example, glycerol, propyleneglycol, and liquid polyethylene glycol, or the like), suitable mixturesthereof, and vegetable oils. The proper fluidity can be maintained, forexample, by the use of a substance, such as lecithin (e.g. a coating),by the maintenance of the required particle size in the case ofdispersion and by the use of surfactants. The prevention of the actionof microorganisms can be brought about by any of the preservativesdescribed herein, or as would be known to those skilled in the art,including various antibacterial and antifungal agents, for example,parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like.In many cases, it will be preferable to include isotonic agents, forexample, sugars or sodium chloride. Prolonged absorption of theinjectable compositions can be brought about by the use in thecompositions of agents delaying absorption, for example, aluminummonostearate.

Sterile injectable solutions are prepared by incorporating the activecompounds in the required amount in the appropriate solvent with,various of the other ingredients enumerated above, as required, followedby filtered sterilization. Generally, dispersions are prepared byincorporating the various sterilized active ingredients into a sterilevehicle which contains the basic dispersion medium and the requiredother ingredients from those enumerated above. In the case of sterilepowders for the preparation of sterile injectable solutions, thepreferred methods of preparation are vacuum-drying and freeze-dryingtechniques which yield a powder of the active ingredient plus anyadditional desired ingredient from a previously sterile-filteredsolution thereof. The preparation of more, or highly, concentratedsolutions for direct injection is also contemplated, where the use ofDMSO as solvent (although DMSO may not now be a permitted human drug) isenvisioned to result in extremely rapid penetration, delivering highconcentrations of the active agents to a small area.

Upon formulation, solutions will be administered in a manner compatiblewith the dosage formulation and in such amount as is therapeuticallyeffective. The formulations are easily administered in a variety ofdosage forms, such as the type of injectable solutions described above,but drug release capsules and the like can also be employed.

For parenteral administration in an aqueous solution, for example, thesolution should be suitably buffered if necessary and the liquid diluentfirst rendered isotonic with sufficient saline or glucose. Theseparticular aqueous solutions are especially suitable for intravenous,intramuscular, subcutaneous and intraperitoneal administration. In thisconnection, sterile aqueous media which can be employed will be known tothose of skill in the art in light of the present disclosure. Forexample, one dosage could be dissolved in 1 ml of isotonic NaCl solutionand either added to 1000 ml of fluid or injected at the proposed site ofinfusion, (see for example, “Remington's Pharmaceutical Sciences” 15thEdition, pages 1035-1038 and 1570-1580). Some variation in dosage willnecessarily occur depending on the condition of the subject beingtreated. The person responsible for administration will, in any event,determine the appropriate dose for the individual subject.

The active GHB may be formulated within a therapeutic mixture tocomprise about 100 to about 10,000 milligrams per dose. Multiple dosescan also be administered.

In addition to the compounds formulated for parenteral administration,such as intravenous or intramuscular injection, other pharmaceuticallyacceptable forms include, e.g., tablets or other solids; liposomalformulations; time release capsules; and any other form currently used,including creams, which then may be admixed with an aqueous medium fororal administration.

One may also use nasal solutions or sprays, aerosols or inhalants in thepresent invention. Nasal solutions are usually aqueous solutionsdesigned to be administered to the nasal passages in drops or sprays.Nasal solutions are prepared so that they are similar in many respectsto nasal secretions, so that normal ciliary action is maintained. Thus,the aqueous nasal solutions usually are isotonic and slightly bufferedto maintain a pH of 5.5 to 6.5, though other pH ranges disclosed hereinthe specific examples, such as pH 3 to about pH 9, or pH 6 to about 7.5,are contemplated. In addition, preservatives, similar to those used inophthalmic preparations, and appropriate drug stabilizers, if required,may be included in the formulation. Various commercial nasalpreparations are known and include, for example, antibiotics andantihistamines and are used for asthma prophylaxis.

The preferred oral formulations may include such normally employedexcipients, as, for example, pharmaceutical grades of xylitol, mannitol,lactose, starch, magnesium stearate, sodium saccharin, cellulose,magnesium carbonate and the like. These compositions can take the formof solutions, suspensions, tablets, pills, capsules, sustained releaseformulations or powders to be admixed with an aqueous medium. In certaindefined embodiments, oral pharmaceutical compositions will comprise aninert diluent or assimilable edible carrier, or they may be enclosed inhard or soft shell gelatin capsule, or they may be compressed intotablets, or the GHB may be packaged separately from or in combinationwith the excipients, salts, flavorings or any other components describedherein, to be admixed with an aqueous medium for oral or injectableformulations, or they may be incorporated directly with the food (i.e. abeverage) of the diet.

For oral therapeutic administration, the active compounds may beincorporated with excipients and used in the form of tablets, buccaltablets or tabs, troches, capsules, elixirs, suspensions, syrups,wafers, and the like, to be admixed with an aqueous medium. Suchcompositions and preparations should contain at least 0.1% of activecompound. The percentage of the compositions and preparations may, ofcourse, be varied and may conveniently be between about 2 to about 75%of the weight of the unit, or preferably between 25-60%. The amount ofactive compounds in such therapeutically useful compositions is suchthat a suitable dosage will be obtained.

The tablets, troches, pills, capsules and the like may also contain thefollowing: a binder, natural as gum tragacanth, acacia, cornstarch, orgelatin or synthetic as polyvinyl acetate; excipients, such as dicalciumphosphate; a disintegrating agent, such as corn starch, potato starch,alginic acid and the like; a lubricant, such as magnesium stearate; anda sweetening agent, such as sucrose, lactose or saccharin may be addedor a natural or synthetic flavoring agent. When the dosage unit form isa capsule for admixing with a specific volume of an aqueous medium, itmay contain, in addition to materials of the above type, a liquidcarrier. Various other materials may be present as coatings or tootherwise modify the physical form of the dosage unit. For instance,tablets, pills, or capsules may be coated with sugar, natural orsynthetic polymers, or both. A syrup or elixir may contain the activecompounds, sucrose as a sweetening agent, a preservative, a dye and/or aflavoring.

Additionally, any excipient, salt, acid, pH-mediating, adjusting orbuffering compound or agent, flavoring, solution, solvent, dispersion,glycerol, glycol, oil, antibacterial and antifungal agents, antibioticsand antihistamines, binders, disintegrating agents, lubricants,sweetening agents, or any other additive or ingredient from thoseenumerated above or in the examples, or in any pharmaceuticallyacceptable composition or carrier described herein, or as would be knownby one of skill in the art, is contemplated for use in aqueous mediumsor solid forms of the GHB compositions of the invention. One or more ofthese compositions may be packaged with GHB or packaged separately fromGHB prior to consumption. If packaged separately, useful compositions ofGHB may be obtained by mixing GHB with the other components with anaqueous medium prior to consumption. Such components may be packaged ina kit, described below.

Therapeutic kits of the present invention are kits comprising GHB. Suchkits will generally contain, in suitable container, a pharmaceuticallyacceptable formulation of GHB. The kit may have a single container, orit may have distinct container for each component, or distinct containerfor various combinations of components.

When the components of the kit are provided in one or more liquidformulations, the liquid formulation is an aqueous medium, with asterile aqueous solution being particularly preferred. The GHBcompositions may also be formulated into a syringeable composition. Inwhich case, the container means may itself be a syringe, pipette, vial,ampule or other such like apparatus, from which the formulation may beapplied to an infected area of the body, injected into an animal, oreven applied to and mixed with the other components of the kit.

However, the components of the kit may be provided as dried powder(s).When reagents or components are provided as a dry powder, the powder canbe reconstituted by the addition of a suitable solvent. It is envisionedthat the solvent may also be provided in another container means.

The container means will generally include at least one vial, test tube,flask, bottle, pouch syringe or other container means, into which theGHB formulation or components thereof are placed, preferably, suitablyallocated. The kits may also comprise a second container means forcontaining a sterile, pharmaceutically acceptable buffer or otherdiluent.

The kits of the present invention will also typically include a meansfor containing the vials in close confinement for commercial sale, suchas, e.g., injection or blow-molded plastic containers into which thedesired vials are retained.

In certain embodiments, the kits of the present invention contain one ormore bottles of liquid formulation comprising GHB, two dosing cups withchild-resistant caps, a liquid measuring device and a medication guide.

Irrespective of the number or type of containers, the kits of theinvention may also comprise, or be packaged with, an instrument forassisting with the injection/administration or placement of the GHBcomposition within the body of an animal. Such an instrument may be adrinking cup, syringe, pipette, or any such medically approved deliveryvehicle.

6.2.5 Methods of Treatment

The compositions and formulations comprising mixed salts of GHB,disclosed herein, are also contemplated to be useful in the treatment ofany of these disorders or conditions in patients. GHB has also been usedalone as a narcotic in patients with a terminal carcinomatous state. GHBhas been used with other analgesics, neuroleptics, or with a subliminalbarbiturate dose for use as an anesthesia. It is also contemplated thatthe GHB compositions and formulations disclosed herein may be used as anarcotic, hypnotic, or as a soporific. It is further contemplated thatthe GHB compositions and formulations comprising mixed salts of GHB,disclosed herein, may be used in combination with analgesics,neuroleptics or barbiturates for use as an anesthesia.

The GHB compositions and formulations comprising mixed salts of GHB,disclosed herein, may be prepared and administered by any of the meansdescribed herein, particularly those described in the section“Formulations” and the examples, or by any means as would be known tothose of skill in the art.

Accordingly, in certain aspects, are methods of treatment comprisingadministration to a patient of the compositions or formulationscomprising mixed salts GHB disclosed herein.

In certain embodiments, the compositions or formulations comprisingmixed salts of GHB, disclosed herein, are useful in the treatment ofcataplexy or daytime sleepiness in a patient who has been diagnosed withnarcolepsy.

In certain embodiments, the compositions or formulations comprisingmixed salts of GHB, disclosed herein, are useful in the treatment ofconditions responsive to GHB, for example, sleep disorders such asapnea, sleep time disturbances, narcolepsy, cataplexy, sleep paralysis,hypnagogic hallucination, sleep arousal, insomnia, and nocturnalmyoclonus.

In certain embodiments, the methods of treatment comprisingadministration of the compositions or formulations comprising mixedsalts GHB disclosed herein.

In certain embodiments, the method comprises oral administration of thecompositions or formulations comprising mixed salts GHB, disclosedherein, in a multiple dosage regimen.

In certain embodiments, the multiple dosage regimen comprises one ormore steps, as follows: (i) diluting an aqueous solution comprisingabout 500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a first dose of about 1 to about 10 grams ofthe mixture of salts; (ii) diluting an aqueous solution comprising about500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a second dose of about 1 to about 10 grams ofthe mixture of salts; (iii) orally administering to a patient havingnarcolepsy the first dose within an hour prior to initial sleep onset;and (iv) orally administering to the patient having narcolepsy thesecond dose within 2.5 to 4 hours following initial sleep onset.

In certain embodiments, the multiple dosage regimen comprises one ormore steps, as follows: (i) diluting an aqueous solution comprisingabout 500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a first dose of about 2.25 to about 4.5 gramsof the mixture of salts; (ii) diluting an aqueous solution comprisingabout 500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a second dose of about 2.25 to about 4.5 gramsof the mixture of salts; (iii) orally administering to a patient havingnarcolepsy the first dose within an hour prior to initial sleep onset;and (iv) orally administering to the patient having narcolepsy thesecond dose within 2.5 to 4 hours following initial sleep onset.

In certain embodiments, the multiple dosage regimen comprises one ormore steps, as follows: (i) diluting an aqueous solution comprisingabout 500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a first dose of about 1.0 to about 4.5 gramsof the mixture of salts; (ii) diluting an aqueous solution comprisingabout 500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a second dose of about 1.0 to about 4.5 gramsof the mixture of salts; (iii) orally administering to a patient havingnarcolepsy the first dose within an hour prior to initial sleep onset;and (iv) orally administering to the patient having narcolepsy thesecond dose within 2.5 to 4 hours following initial sleep onset.

In certain embodiments, the multiple dosage regimen comprises one ormore steps, as follows: (i) diluting an aqueous solution comprisingabout 500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a first dose of about 4.5 to about 10 grams ofthe mixture of salts; (ii) diluting an aqueous solution comprising about500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a second dose of about 4.5 to about 10 gramsof the mixture of salts; (iii) orally administering to a patient havingnarcolepsy the first dose within an hour prior to initial sleep onset;and (iv) orally administering to the patient having narcolepsy thesecond dose within 2.5 to 4 hours following initial sleep onset.

In certain embodiments, the multiple dosage regimen comprises one ormore steps, as follows: (i) diluting an aqueous solution comprisingabout 500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a first dose of about 3.0 to about 10 grams ofthe mixture of salts; (ii) diluting an aqueous solution comprising about500 mg/mL of the mixture of salts of gamma-hydroxybutyrate with anaqueous medium to provide a second dose of about 3.0 to about 10 gramsof the mixture of salts; (iii) orally administering to a patient havingnarcolepsy the first dose within an hour prior to initial sleep onset;and (iv) orally administering to the patient having narcolepsy thesecond dose within 2.5 to 4 hours following initial sleep onset.

It will be understood, however, that the specific dose level andfrequency of dosage for any particular patient may be varied and willdepend upon a variety of factors including: the metabolic stability andlength of action, the age, body weight, general health, sex, diet, modeand time of administration, rate of excretion, drug combination, theseverity of the particular condition, and the host undergoing therapy.

6.2.6 Methods of Making

In certain aspects, provided herein are methods of making thecompositions or formulations comprising mixed salts GHB disclosedherein. Several different methods of making have been reported in theliterature (see, e.g., U.S. Pat. Nos. 4,393,236; 4,983,632; 6,472,431;Ferris and Went, 2012, Forensic Science International 216: 158-162).Those skilled in the art will recognize that these methods can beincorporated in the making of the compositions or formulationscomprising mixed salts GHB disclosed herein.

In certain embodiments, mixtures of GHB salts can be made by directreaction of GBL with an aqueous mixture of one of more of the followingbases: sodium hydroxide, potassium hydroxide, calcium hydroxide, andmagnesium hydroxide. After reaction the mixture may then be filteredunder mild vacuum.

In certain embodiments, a solvent, such as water, is used to dissolvethe GHB salt mixture to a desired concentration, for example, byadjusting the amount of water in the mixture.

In certain embodiments, the concentration of a GHB salt solution isadjusted by concentrating the mixture using standard methods, such asevaporators, reverse osmosis, and similar techniques known to thoseskilled in the art.

In certain embodiments, the method of making comprises reactinggamma-butyrolacetone (GBL) with one or more bases selected from thegroup consisting of sodium hydroxide, potassium hydroxide, magnesiumhydroxide, and calcium hydroxide.

In certain embodiments, the reaction is carried out in a single vessel.For example, a mixture of Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂ may bemade by direct addition of GBL to in a single vessel containing anaqueous mixture of sodium hydroxide, potassium hydroxide, magnesiumhydroxide, and calcium hydroxide.

In certain embodiments, the reaction is carried out in multiple vesselsand the product is subsequently combined. For example, Ca.(GHB)) may bemade by direct addition of GBL to aqueous sodium hydroxide, and theproduct combined with Mg.(GHB)₂.

In certain embodiments, the methods of making include methods of makingthe pharmaceutical compositions and formulations disclosed herein.

The following examples are included to demonstrate preferred embodimentsof the invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the examples which follow representtechniques discovered by the inventor to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

7. EXAMPLES

7.1 Example 1: Synthesis of Mixture A

The following synthetic examples provide exemplary syntheses of mixtureof oxybate salts. Alternate methods of synthesizing mixtures of oxybatesalts, including methods of synthesizing additional salts of oxybate aredescribed below; still other alternate synthetic methods will beapparent to those skilled in the art.

Mixture A of Table 2 was arrived by direct reaction of GBL with anaqueous mixture of four bases. Sodium hydroxide (Sigma Aldrich Reagent,98.50% assay), potassium hydroxide (Sigma Aldrich ACS Reagent, 86.72%assay), calcium hydroxide (Sigma Aldrich ACS Reagent, 99.0% assay), andmagnesium hydroxide (Sigma Aldrich Reagent, 99.5% assay) were weighed as1.398 grams, 7.337 grams, 6.268 grams, and 2.611 grams, respectively,into a 100 ml Pyrex volumetric flask. To this, 68.03 grams of water(ultrapure by reverse osmosis) was added with mixing and subsequentlyallowed to cool. GBL (99.9% purity) was added in 1 ml aliquots for atotal of 34.38 grams. During addition, reaction occured immediately andheat was evolved. With cooling, the temperature did not exceed 80° C.After GBL addition, the mixture was placed in a temperature-controlledwater bath kit to 80° C. with mixing, and allowed to react to completionin about 3 hours. The mixture was then filtered under mild vacuum,cooled to room temperature, and characterized for final pH, assay (bytitration), solids content (by loss on drying), and purity (byreverse-phase gradient HPLC). The pH was 8.04, assay was 100.8% oftarget, solids content was 42.25%, and impurities consisted ofun-reacted GBL (0.169%) and hydroxybutyl butyric acid (HBBA, 0.083%).The filtered solution was clear. The details of this and the mixtures ofExamples 2-5 (including, e.g., Mixtures B-G) are provided in Tables 1-6.

Example calculations of molar equivalents and % wt/wt for salt mixturesare shown below for Mixture A in Table 1. For Mixture A, 34.38 g of99.9% GBL were charged, which is (34.38×0.999/68.089×1000)=399.0 mMol.The total base equivalents charged were 404.40 mEq. Hence, the excessbase was ((404.40-399.0)/(399.0×100%))=1.35%.

TABLE 1 Example calculation Base Grams Base Stoich. Base % molar SaltSalt mass Salt Conc Base MW Purity Amount mMols Ratio mEQ equlv GHB SaltMW grams wt/wt % mg/ml NaOH 40.00 98.50% 1.398 34.43 1 34.43 8.5% Na•GHB126.09 4.34 8.5% 42.61 KOH 56.11 86.72% 7.337 113.40 1 113.40 28.0%K•GHB 142.20 16.12 31.4% 158.29 Ca(OH)₂ 74.10 99.00% 6.268 83.74 2167.49 41.4% Ca•(GHB)₂ 246.27 20.62 40.2% 202.46 Mg(OH)₂ 58.32 99.50%2.611 44.55 2 89.09 22.0% Mg•(GHB)₂ 230.50 10.27 20.0% 100.80 Total17.614 276.11 404.40 100.0% 51.36 100.0% 504.17 Base Each of four basesused in this example Base MW Molecular weight of the base Purity Purityprovided by manufacturer. It is assumed that impurities arenon-reactive. Gram Amount Amount, in grams, of each base charged to thereaction Base mMols Corresponding amount, in millimoles, of pure base(that is, Purity × Gram-Amount × 1000/Base-MW) Stoichiometry Ratio Thenumber of GHB moles reacted with each mole of base Base mEQ Baseequivalents for reaction with GHB (that is, Base-mMols ×Stiochiometry-Ratio). This is also the Oxybate or GHB equivalents value.% molar equiv GHB Molar composition of salts expressed as Percent ofOxybate Equivalents Salt The oxybate salt species Salt MW Molecularweight of the oxybate salt Salt-mass-grams Mass of salt produced byreaction (that is, Base-mMols × Salt-MW/1000) Salt wt/wt % Normalizedweight percent Conc (mg/ml) Concentration in mg/ml equivalent to a 3.97MNa-GHB solution (500 mg/ml sodium oxybate). That is, 3.97 × (%equiv-GHB) × (Salt-MW)/(Stoich. Ratio)

TABLE 2 Reaction Mixture (grams) Reaction Mixture (grams) Mixture NaOHKOH MgOH₂ CaOH₂ GBL Water Total A 1.398 7.337 2.611 6.268 34.38 68.03120.0 B 1.792 9.383 0.0 8.039 34.5 66.38 120.1 C 0.000 0.000 5.9 0.00017.22 36.87  60.0 D — — — — — — — E 11.206  58.611 21.713 50.272  276.7538.70  957.2 F 1.404 7.352 2.612 6.276 34.33 68.00 120.0 G 4.805 7.331.759 4.225 34.45 67.52 120.1

TABLE 3 Concentration of Oxybate salt (wt/wt %) Concentration of oxybatesalt (wt/wt %) Mixture Na•GHB K•GHB Mg•GHB₂ Ca•GHB₂ Total A 8.45 31.4019.99 40.16 100.0 B 10.57 39.18 0.00 50.24 100.0 C 0.00 0.00 100.00 0.00100.0 D 8.47 31.36 19.97 40.22 100.0 E 8.40 31.09 20.61 39.92 100.0 F8.49 31.42 19.97 40.14 100.0 G 28.79 31.07 13.34 26.80 100.0

TABLE 4 Concentration of Oxybate Salt (mg/mL) Concentration of oxybatesalt (mg/mL) Mixture Na•GHB K•GHB Mg•GHB₂ Ca•GHB₂ Total A 42.6 158.3100.8 202.5 504.2 B 54.7 202.7 0 259.9 517.3 C 0 0 457.5 0 457.5 D 42.7158.1 100.7 202.8 504.2 E 42.3 156.6 103.8 201.1 503.7 F 42.8 158.4100.7 202.4 504.2 G 146.5 158.1 67.9 136.4 508.9

TABLE 5 Concentration of Oxybate Salt (molar equiv.) Percent of oxybate(molar equiv.) Mixture Na•GHB K•GHB Mg•GHB₂ Ca•GHB₂ Total A 8.5 28.022.0 41.4 100.0 B 10.9 35.9 0.0 53.2 100.0 C 0.0 0.0 100.0 0.0 100.0 D8.5 28.0 22.0 41.5 100.0 E 8.4 27.7 22.7 41.1 100.0 F 8.5 28.1 22.0 41.4100.0 G 29.2 28.0 14.8 27.9 100.0

TABLE 6 Results and Characterization of Formulas Titration HPLC ReactionBase Assay LOD % Area % Impurities Mixture Time (h) Yield (%) Excess pH(% target) Solids GBL HBBA A 3 93 1.3 8.04 100.8 42.25 0.169 0.083 B 394 0.8 8.47 100.3 42.87 0.075 0.038 C 3 90 1.0 6.62 96.8 35.87 0.6520.270 D — — — 8.05 99.6 41.30 0.189 0.097 E 6.5 95 1.6 8.16 103.3 41.910.201 0.052 F 3.5 90 1.6 8.00 101.5 41.97 0.167 0.131 G 3.5 88 1.1 8.2797.6 41.06 0.143 0.061

7.2 Example 2: Synthesis of Mixture B

Mixture B, containing sodium, potassium, calcium, but not magnesium, wasalso arrived by direct reaction of GBL with an aqueous mixture of thebases. Separately, magnesium oxybate (Mixture C) was made in the samemolar strength by reaction of GBL with an aqueous suspension ofmagnesium hydroxide. The latter reaction was considerably slower, andespecially slow as the reaction neared completion and most of themagnesium hydroxide was depleted. Both batches were then filtered. Thetwo mixtures were then combined in a ratio of 0.78:0.22 (v/v) to arriveat Mixture D which is the same composition as Mixture A. Product made inthis “2-pot” method has properties comparable to that of the “1-pot”method, but in some circumstances may be preferred.

7.3 Example 3: Synthesis of Mixture E

Mixture E was produced at approximately 8-fold larger batch size in a1-liter vessel. The bases were weighed into the vessel, and water wasquickly added with stirring. The temperature rose from 21° C. to 40° C.and was allowed to cool to 23° C. by immersion in a cold water bath. Thevessel was then removed from cooling, and GBL was then added in 10 galiquots while recording temperature. The temperature rose steadily witheach aliquot of GBL added until between 75% and 79% addition, at whichtime the temperature began to fall slowly despite GBL addition, due tocooling. This phenomenon was consistent with the relatively fastreactions of sodium, potassium, and calcium hydroxides, and the muchslower reaction of magnesium hydroxide, as the latter was about 23% bystoichiometry. After GBL addition, the vessel was then placed in a waterbath controlled to 80° C. After 6.5 hours, the product was filtered andcharacterized for pH, assay, solids content, and purity.

7.4 Example 4: Synthesis of Mixture F

Although it is generally more convenient to add the GBL to a stirredmixture of bases in water, the reverse addition order produced acomparable product. In producing Mixture F, GBL was first loaded into a100 ml reaction vessel. Separately, an aqueous mixture of the four baseswas prepared with stirring, and this mixture was then added to the GBLin 1 ml aliquots. The reaction mixture was then placed in a 80° C. waterbath for 3.5 hours, recovered after filtration, and characterized forpH, assay, % solids, and purity. The results are generally comparable tothose of Mixture A, which was produced using the opposite order ofaddition.

7.5 Example 5: Synthesis of Mixture G

Mixture G was arrived by direct addition of gamma butyrolactone (GBL) toan aqueous mixture of the four bases. After GBL addition, the mixturewas placed in a temperature-controlled water bath kit to 80° C. withmixing, and allowed to react to completion in about 3.5 hours. Themixture was then filtered under mild vacuum, cooled to room temperature,and characterized for final pH, assay (by titration), solids content (byloss on drying), and purity (by reverse-phase gradient HPLC). The pH was8.27, assay was 97.6% of target, solids content was 41.06%, andimpurities consisted of unreacted GBL (0.143%) and hydroxybutyl butyricacid (HBBA, 0.061%). The filtered solution was clear.

7.6 Example 6: Synthesis of Mixtures H and I

The oxybate salt mixture composition can be adjusted to produce amixture having the same overall mass potency as sodium oxybate. In otherwords, the weighted-average molecular weight per molar equivalent ofoxybate is the same (126.09). Thus, the absolute dosing of the oxybatesalt mixture, in grams of drug substance, is the same as sodium oxybate.This is particularly useful for avoiding potential confusion andreducing medication errors as a result of switching patients from asodium oxybate product to a mixed salt product. In other words, 6.0grams dosing of sodium oxybate is also 6.0 grams dosing of the saltmixture. This feature cannot be achieved in alternative single-salts ofoxybate.

Two such formulations were produced by the similar procedure as outlinedin Example 1. Sodium hydroxide (Sigma Aldrich Reagent, 98.20% assay),potassium hydroxide (Sigma Aldrich ACS Reagent, 86.72% assay), calciumhydroxide (Sigma Aldrich ACS Reagent, 99.0% assay), and magnesiumhydroxide (Sigma Aldrich Reagent, 99.5% assay) were weighed as indicatedin Table 7, respectively, into a 100 ml Pyrex bottle. To this, water(ultrapure by reverse osmosis) was added with mixing, and finally GBL(99.9% purity) was added in about 2 ml aliquots. During addition,reaction occured immediately and heat was evolved. After GBL addition,the mixture was placed in a temperature-controlled water bath kit to 80°C. with mixing, and allowed to react to completion. After four hours,the conversion from reaction was about 99.5% and 98.5% (as measured byresidual GBL). To speed completion, a small amount of magnesiumhydroxide was added. After 5.25 hours, the mixtures were then filteredunder mild vacuum and cooled to room temperature. The filtered solutionswere clear. The solutions were characterized for final pH, assay bytitration, solids content by evaporation at 150° C. (4 h) followed byequilibration at 60° C., and purity by reverse-phase gradient HPLC. Themolecular weight per oxybate equivalent of each mixture was calculatedfrom the assay and solids content results, and were in reasonableagreement with sodium oxybate (127.0 and 126.4 g/mol-equiv vs. 126.09for sodium oxybate).

TABLE 7 Conditions and Results Mixture H Mixture I Target Formula (%molar equiv): Na-GHB 8.0% 0.0% K-GHB 23.0% 33.0% Ca-(GHB)₂ 48.0% 25.0%Mg-(GHB)₂ 21.0% 42.0% Amounts charged (grams): NaOH 1.329 0 KOH 6.0078.623 Ca(OH)₂ 7.268 3.776 Mg(OH)₂ 2.495 4.977 GBL 34.35 34.41 Water 68.468.3 Additional Mg(OH)₂ to finish rxn 0.46 g 1.155 g Productcharacterization: pH 8.22 8.41 Oxybate assay (mEq/g) 3.192 3.117 Solidscontent (%) 40.54 39.41 MW per oxybate (g/Eq) 127.0 126.4 (As % of SXBMW) 100.7 100.3 Impurities: GBL 0.08 0.07 HBBA Not found Not found

7.7 Example 7: Gastrointestinal Motility Study

This example demonstrates that the pharmaceutical compositionscomprising mixed salts of oxybate, disclosed herein, display acceptablepharmacokinetic properties (measured as GastroIntestinal transit rates),similar to those of Xyrem®.

In this study, Saline, Xyrem® solution (Sodium Oxybate), and twoformulations (comprising Mixtures A and G, corresponding to Examples 1and 5, respectively; hereafter referred to as “mixed salt formulations”in Example 7) were dosed orally, followed by oral administration ofnon-absorbable marker, Carmine, into male CD-1 mice. Following dosing,the small intestine, from the pylorus to the cecum, was removed. Thedistance the marker compound traveled was measured and calculated as apercentage of the total length of the small intestine. The animals inGroups 2 through 4 showed lethargy after receiving the test compounds.The animals in Group 1 showed normal activity during the study. Thedetails of the study are provided below and are summarized in Table 8.

1.0 Objective: Evaluation of the GI motility of Xyrem® (Sodium Oxybate)and two other mixed salt formulations after oral administration in amale CD-1 mouse GI motility model˜dosing and sampling only.

2.0 Experimental:

a. Materials

-   -   i. The test compounds were provided by Jazz Pharmaceuticals,        3180 Porter Drive, Palo Alto, Calif. 94304.    -   ii. Male CD-1 mice were obtained from Hilltop Lab Animals,        Scottdale, Pa. 15683.        b. Dosing Solution Preparation    -   All dosing solutions were prepared fresh on the day of dosing        and were dosed within one hour of preparation.        c. Animal Dosing    -   i. Animals were housed five per cage. All mice were identified        by a cage label and tail mark. A single room was used for this        study.    -   ii. The animals were healthy at the start of the study. The        mice, ranged in weight from 25 to 31 g.    -   iii. The duration of acclimation was two days.    -   iv. Animals were supplied with water and a commercial rodent        diet ad libitum prior to the study initiation. Food was withheld        from the animals for a minimum of twelve hours before the study        and during the study. Water was supplied ad libitum.    -   v. The animals were assigned randomly to treatment groups upon        arrival.    -   vi. The study was not blinded.    -   vii. Animals were dosed via the appropriate route at time 0 on        the appropriate day.        d. Sample Collection    -   At 20 minutes post Carmine dose, the mice were euthanized and        the small intestine from the pylorus to the cecum was removed.        The distance the marker compound traveled was measured and        calculated as a percentage of the total length of the small        intestine.

TABLE 8 Study Design Dosing Solution Conc. mg/mL (Sodium Oxybate DosingTreatment Test Dosing Animals Dose Molar Equivalent Volume Sampling TimeGroup Compound Route N = mg/kg basis) mL/kg Vehicle Point 1* NA PO 10 NANA 5 Saline 20 minutes post marker compound dose 2* Xyrem ® PO 10 200 405 Sterile 20 minutes post solution Water marker compound (Sodium doseOxybate) 3* Mixture G PO 10 200 40 5 Sterile 20 minutes post Watermarker compound dose 4* Mixture A PO 10 200 40 5 Sterile 20 minutes postWater marker compound dose *20 minutes after test compound dose, 6%Carmine (w/v) in 0.5% methyl cellulose, low viscosity in tap water wasadministered PO at 0.3 mL/mouse (Carai et al., Life Sciences 70 (2002)3059-3067). Mice were sacrificed 20 minutes after this second dose.

Salt Mixtures:

Percent of oxybate (molar equiv.) Treatment Group Mixture Na•GHB K•GHBCa•(GHB)₂ Mg•(GHB)₂ 3 G 29.2% 28.0% 28.0% 14.8% 4 A 8.5% 28.0% 41.5%21.9%

3.0 Results:

a. Observations

-   -   Animals receiving the Xyrem® solution and two other mixed salt        formulations orally, showed lethargy. The animals in Group 1        showed normal activity during the study.        b. Data    -   See Table 9 and FIG. 1.

TABLE 9 Results Group 1, Saline Mouse # 1 2 3 4 5 6 7 8 9 10 Mean SEMsmall 41.5 38.0 42.0 32.0 36.0 38.0 35.5 39.5 33.5 36.5 37.3 1.0intestine length (cm) marker 22.0 25.0 18.0 17.0 16.0 21.5 21.5 14.518.5 18.0 19.2 1.0 traveled (cm) GI transit 53.0 65.8 42.9 53.1 44.456.6 60.6 36.7 55.2 49.3 51.8 2.7 (%) Group 2, Xyrem ® solution (SodiumOxybate) Mouse # 11 12 13 14 15 16 17 18 19 20 small 38.0 31.5 37.0 37.532.0 38.0 37.5 42.0 36.0 40.5 37.0 1.0 intestine length (cm) marker 11.010.5 9.5 9.0 16.0 21.0 7.5 12.0 16.5 16.0 12.9 1.3 traveled (cm) GItransit 28.9 33.3 25.7 24.0 50.0 55.3 20.0 28.6 45.8 39.5 35.1 3.8 (%)Group 3, Salt Mixture G Mouse # 21 22 23 24 25 26 27 28 29 30 small 42.539.0 39.0 32.0 38.5 38.0 32.5 39.0 40.0 37.5 37.8 1.0 intestine length(cm) marker 10.5 16.0 14.0 10.5 6.5 10.5 11.5 9.0 17.0 15.0 12.1 1.1traveled (cm) GI 24.7 41.0 35.9 32.8 16.9 27.6 35.4 23.1 42.5 40.0 32.02.7 transit (%) Group 4, Salt Mixture A Mouse # 31 32 33 34 35 36 37 3839 40 small 38.0 36.0 36.0 35.0 38.5 41.0 40.0 38.0 40.0 38.0 38.1 0.6intestine length (cm) marker 8.0 10.0 12.0 12.0 11.0 13.0 14.0 10.5 8.514.0 11.3 0.7 traveled (cm) GI transit 21.1 27.8 33.3 34.3 28.6 31.735.0 27.6 20.3 36.8 29.7 1.7 (%)

4.0 Conclusions: Saline, Xyrem® solution (Sodium Oxybate), and two othermixed salt formulations were dosed orally, followed by oraladministration of non-absorbable marker, Cattnine, into male CD-1 mice.At 20 minutes post-Carmine dose, the mice were euthanized and the smallintestine from the pylorus to the cecum was removed. The distance themarker compound traveled was measured and calculated as a percentage ofthe total length of the small intestine. Test compound treated groupsshowed lower transit rate compared to the control (saline) group;whereas Mixtures A and G displayed transit rates similar to those ofXyrem®.

7.8 Example 8: Microbial Challenge and Stability Testing of Formulations

This example provides protocols for microbial challenge and stabilitytesting of the formulations disclosed herein.

1.0 Objective: To prepare, test and evaluate multiple formulations usingalternative mixed salts of gamma-hydroxybutyrate.

2.0 Experimental:

a. Preparation

-   -   Method for preparation of various formulations: For a one liter        quantity of product, add the mixture of salts of GHB in 500 ml        of purified and stir until dissolved. Prepare a 10% solution of        the acid (Malic or Citric) and add slowly to the solution. The        solution should be monitored for pH and temperature and both        variables recorded at reasonable intervals (every 10 or 15        minutes). When the target pH is attained, the solution will        be Q. S. to 1 liter, and pH rechecked and recorded. The final        solutions will be filtered through 10 μm filters and 200 mL        dispensed into 5 amber PET bottles with closures. Two bottles        are used for microbial challenge studies and the remaining        bottles are used for the limited stability evaluation.        b. Testing    -   Formulations are tested by two methods of evaluation:    -   i. Limited stability evaluation: (1) Storage Conditions:        25° C. (2) Pull Points: Day 0 (day of preparation), and day        28 (3) Testing Requirements: appearance (visual), potency        (HPLC), impurities (HPLC) and pH.    -   ii. Microbial challenge: (1) Storage Conditions: Microbial        challenge studies of above formulations are set up with 5        microorganisms and stored for 28 days at 20-25° C., per USP <51>        Eighth Supplement. (2) Microorganisms: After a sufficient        quantity of each formulation is prepared, aliquots are        inoculated with 5 microorganisms at a concentration of at least        10⁵ microorganisms/cc: (a) Escherichia coli, ATCC 8739 (b)        Pseudomonas aeruginosa, ATCC 9027 (c) Staphylococcus aureus,        ATCC 6538 (d) Aspergillus niger, ATCC 18404 (e) Candida        albicans, ATCC 10231. (3) Time Points:    -   A determination of the viable cell concentration in each        inoculated container is performed after 0, 1, 3, 7, 14, 21 and        28 days.

3.0 Results:

i. Limited stability evaluation: Formulations are determined to bechemically stable if the level of GBL is 0.15% or less of theformulation as per the ICH guidelines for shelf-life determination.

ii. Microbial challenge: Formulations are determined to “Pass or Fail”based upon the USP criteria for perservative effectiveness which states:For Bacteria, “Not less than 1 log reduction from the initial microbialcount at 14 days and no increase from the 14 days count at 28 days”; andfor yeast and molds, “No increase from the initial calculated count at14 and 28 days.” Solutions which met these criteria are designated as“Pass” and those that do not meet these criteria are designated as“Fail”.

7.9 Example 9: Preparation of Pharmaceutical Compositions Comprising aMixture of Salts of GHB

This example provides exemplary pharmaceutical compositions comprisingmixtures of salts of GHB.

Pharmaceutical Composition Comprising Mixture A: A pharmaceuticalcomposition is prepared according to Example 1. The pharmaceuticalcomposition comprises Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂ salts in awt/wt % ratio of about 8%:32%:20%:40%, respectively, at a totalconcentration of about 500 mg/mL. The pH of the composition is measuredto be about 8.0. No preservatives are added to the composition. Thecomposition is tested according to the protocols of Example 8 and isfound to be chemically stable and resistant to microbial growth.

Pharmaceutical Composition Comprising Mixture B: A pharmaceuticalcomposition is prepared according to Example 2. The pharmaceuticalcomposition comprises Na.GHB, K.GHB, and Ca.(GHB)₂ salts in a wt/wt %ratio of about 11%:39%:50% respectively, at a total concentration ofabout 500 mg/mL. The pH of the composition is measured to be about 8.5.No preservatives are added to the composition. The composition is testedaccording to the protocols of Example 8 and is found to be chemicallystable and resistant to microbial growth.

Pharmaceutical Composition Comprising Mixture G: A pharmaceuticalcomposition is prepared according to Example 5. The pharmaceuticalcomposition comprises Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂ salts in awt/wt % ratio of about 29%:31%:13%:27%, respectively, at a totalconcentration of about 500 mg/mL. The pH of the composition is measuredto be about 8.3. No preservatives are added to the composition. Thecomposition is tested according to the protocols of Example 8 and isfound to be chemically stable and resistant to microbial growth.

Pharmaceutical Composition Comprising Mixture H: A pharmaceuticalcomposition is prepared according to Example 6. The pharmaceuticalcomposition comprises Na.GHB, K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂ salts in awt/wt % ratio of about 8%:23%:21%:48%, respectively, at a totalconcentration of about 500 mg/mL. The pH of the composition is measuredto be about 8.3. No preservatives are added to the composition. Thecomposition is tested according to the protocols of Example 8 and isfound to be chemically stable and resistant to microbial growth.

Pharmaceutical Composition Comprising Mixture I: A pharmaceuticalcomposition is prepared according to Example 6. The pharmaceuticalcomposition comprises K.GHB, Mg.(GHB)₂, and Ca.(GHB)₂ salts in a wt/wt %ratio of about 33%:42%:25%, respectively, at a total concentration ofabout 500 mg/mL. The pH of the composition is measured to be about 8.3.No preservatives are added to the composition. The composition is testedaccording to the protocols of Example 8 and is found to be chemicallystable and resistant to microbial growth.

All publications and patent applications cited in this specification areherein incorporated by reference as if each individual publication orpatent application were specifically and individually indicated to beincorporated by reference. Although the foregoing has been described insome detail by way of illustration and example for purposes of clarityof understanding, it will be readily apparent to those skilled in theart in light of the teachings of the specification that certain changesand modifications may be made thereto without departing from the spiritor scope of the appended claims.

What is claimed is:
 1. A method of making a mixture of two or more saltsof gamma-hydroxybutyrate (GHB), the method comprising: contactinggamma-butyrolactone (GBL) with two or more bases selected from the groupconsisting of sodium hydroxide (NaOH), potassium hydroxide (KOH),magnesium hydroxide (Mg(OH)₂), and calcium hydroxide (Ca(OH)₂), in asingle reaction vessel under conditions sufficient to produce a mixtureof two or more salts selected from the group consisting of a sodium saltof gamma-hydroxybutyrate (Na.GHB), a potassium salt ofgamma-hydroxybutyrate (K.GHB), a magnesium salt of gamma-hydroxybutyrate(Mg.(GHB)₂), and a calcium salt of gamma-hydroxybutyrate (Ca.(GHB)₂). 2.The method of claim 1, wherein the GBL is contacted with four basesselected from the group consisting of NaOH, KOH, Mg(OH)₂, and Ca(OH)₂.3. The method of claim 1, wherein the GBL is contacted with three basesselected from the group consisting of NaOH, KOH, Mg(OH)₂, and Ca(OH)₂.4. The method of claim 3, wherein the GBL is contacted with KOH,Mg(OH)₂, and Ca(OH)₂.
 5. The method of claim 1, wherein the GBL iscontacted with two bases selected from the group consisting of KOH,Mg(OH)₂, and Ca(OH)₂.
 6. The method of claim 1, wherein the contactingcomprises addition of the GBL to the bases.
 7. The method of claim 1,wherein the contacting comprises addition of the bases to the GBL. 8.The method of claim 1, wherein the conditions sufficient to produce themixture comprise placing the reaction vessel in a water bath controlledto 80° C. for at least 3 hours.
 9. The method of claim 1, furthercomprising filtering the mixture.
 10. The method of claim 1, wherein theweighted average molecular weight per molar equivalent of the mixture ofsalts is about 126.09.
 11. The method of claim 1, further comprisingadding one or more of a buffering agent, a sweetening agent, a flavoringagent or a coloring agent, optionally in a pharmaceutically acceptablecarrier.
 12. A method of making a mixture of two or more salts of GHB,the Method comprising: contacting GBL with two or more bases selectedfrom the group consisting of NaOH, KOH, Mg(OH)₂, and Ca(OH)₂, in tworeaction vessels under conditions sufficient to produce a mixture of twoor more salts selected from the group consisting of Na.GHB, K.GHB,Mg.(GHB)₂, and Ca.(GHB)₂; wherein the GBL is contacted with Mg(OH)₂ inthe first reaction vessel, and wherein the GBL is contacted with one ormore of NaOH, KOH, and Ca(OH)₂ in the second reaction vessel.
 13. Themethod of claim 12, wherein the mixture comprises Mg.(GHB)₂ andCa.(GHB)₂.
 14. The method of claim 12, wherein the GBL is contacted withthree bases selected from the group consisting of NaOH, KOH, Mg(OH)₂,and Ca(OH)₂.
 15. The method of claim 14, wherein the GBL is contactedwith KOH, Mg(OH)₂, and Ca(OH)₂.
 16. The method of claim 12, wherein thecontacting comprises addition of the GBL to the bases.
 17. The method ofclaim 12, wherein the contacting comprises addition of the bases to theGBL.
 18. A method of making a mixture of four salts of GHB, the methodcomprising: contacting GBL with four bases selected from the groupconsisting of NaOH, KOH, Mg(OH)₂, and Ca(OH)₂, in a single reactionvessel under conditions sufficient to produce a mixture of four saltsselected from the group consisting of Na.GHB, K.GHB, Mg.(GHB)₂, andCa.(GHB)₂.
 19. The method of claim 18, wherein the contacting comprisesaddition of the GBL to the bases.
 20. The method of claim 18, whereinthe contacting comprises addition of the bases to the GBL.
 21. Themethod of claim 18, wherein the conditions sufficient to produce themixture comprise placing the reaction vessel in a water bath controlledto 80° C. for at least 3 hours.
 22. The method of claim 18, furthercomprising filtering the mixture.
 23. The method of claim 18, whereinthe reaction vessel having has at least a one liter capacity.
 24. Themethod of claim 18, wherein the weighted average molecular weight permolar equivalent of the mixture of salts is about 126.09.
 25. The methodof claim 18, further comprising adding one or more of a buffering agent,a sweetening agent, a flavoring agent or a coloring agent, optionally ina pharmaceutically acceptable carrier.